Possible long term cerebral damage from participation in boxing is controversial and may be relevant to the broader issues of head injuries. In many ways, the injuries that occur in amateur boxing, a sport vastly different from professional boxing, are similar to those that occur in other sports and accidents. A study of whether cerebral damage occurs in amateur boxers and a quantitative assessment of the latency to neurobehavioral and other changes due to damage has potentially broad implications. In August, 1988 we completed a baseline study of 486 amateur boxers. The aim of this study has been to determine if changes in selected neuropsychologic, neurologic, and neurophysiologic measures are associated with exposures from boxing. This study is unique in that boxers are identified before any apparent signs of impairment, it is prospective, involves a representative sample of boxers, and make use of a low to nonexposed internal control group. In August, 1988 we were awarded a grant from the NIH (ROI NS26450-01) to conduct the first followup (FUl) study in this population. We requested funds for only a single followup examination because of the uncertainties being able to successfully following this predominantly inner-city, lower SES, young male population. The followup rate to date (95% located, 83% retested) in this population has exceeded our expectations. Data collection will be completed in August, 1990. We propose to conduct two additional followup examinations in this same population, four and six years after the original baseline study. In both the baseline and current FU1 studies, neuropsychologic, electrophysiologic, and neurologic measures have been made in a 4-hour examination. We also propose to extend and finalize the exposure models currently under development. This work includes obtaining detailed histories of competition from the boxers, copies of records to validate subject reports, measuring head acceleration under sparring conditions, and conducting a study comparing subject reports on their boxing style using a structured questionnaire to their observed style of boxing. In data collected to date, the style of boxing reported in a structured interview is a predictor of the outcome of bouts. A refinement of this data is likely to provide a more valid and generalized surrogate of exposure to complement other exposure data currently being collected.